1. Field of the Invention
The present invention relates generally to the field of medical devices. More specifically, the present invention relates to an optical monitor for sudden infant death syndrome.
2. Description of the Related Art
Sudden Infant Death Syndrome (SIDS) is the sudden and unexpected death of an apparently healthy infant, whose death remains unexplained after further medical investigation such as an autopsy. Sudden Infant Death Syndrome is neither a disease, nor can it be a diagnosis for a living baby [1]. SIDS occurs at a rate of approximately 2 per 1,000 live births in the United States and occurs most often (90%) in under six months of age; of these, 18% were preterm infants [2].
One of the events that occurs during Sudden Infant Death Syndrome is a period of apnea (stoppage of breathing) during which it may be possible that the infant may be resuscitated. However, most Sudden Infant Death Syndrome events occur at night when the infant""s caregiver is asleep. Since Sudden Infant Death Syndrome is not normally associated with verbal distress, few infants get a chance to be resuscitated.
Fortunately, the number of Sudden Infant Death Syndrome deaths has decreased at a steady rate. The Sudden Infant Death Syndrome rate for 1995 was 0.87 deaths per 1,000 live births [3]. It is notable that more children die of Sudden Infant Death Syndrome in a year than all children who die of cancer, heart disease, pneumonia, child abuse, AIDS, cystic fibrosis, and muscular dystrophy combined [4]. According to Dr. J. D. DeCristofaro of the University Medical Center Stony Brook, NY, (SIDS Network Internet Website, December 1998), the sibling of a SIDS baby will be on a monitor past the age of the Sudden Infant Death Syndrome death, but a minimum of 6 months. Typically, the parents are not ready to give up the monitor at such time and often continue monitoring for up to a year.
Clearly, some sort of continuous monitoring of the infant for the presence or absence of breathing would be of value. Such a monitor could sound an alarm that would awaken the care-giver when breathing stopped, and further possibly acoustically stimulate the infant thereby stimulating the breathing reflex. In clinics, there exist a multitude of instruments, such as pneumotachometers or plesthymographs that, with little modification, could be used for this purpose. However, these devices are quite expensive and are not practical for use at home, particularly in infants with no history of being at risk for SIDS.
Transthoracic electrical impedance monitors are by far the most frequently applied, have the widest availability in the United States, and are generally efficacious in identifying and alarming on apnea events. With these instruments, however, are some situations where xe2x80x9cbreathsxe2x80x9d are detected during true apneas (false negative) and other cases where apneas are indicated while is breathing (false positive). The former is also a significant concern with impedance monitors thus limiting their usefulness.
Any monitor that accurately reflects the predisposing condition must consistently be alert and understandable to the care giver. In other words, the monitor must be efficacious in recognizing apnea and capable of triggering an alarm for prolonged apnea. Short periods of apnea (15 seconds) may not be fatal to an infant, but prolonged apnea (20 seconds) is abnormal [2]. In addition, the monitor must be capable of recognizing its own internal operating functions to assure proper and uninterrupted operation. Ideally, it must be noninvasive and easy to use and understand. Other desirable features would be the capability of collecting and archiving patterns surrounding significant events for later analysis. These could include estimation of tidal volume, the identification of heart rate patterns and variability as well as cardiac arrhythmias.
Therefore, the prior art is deficient in the lack of effective apparatus and/or means for monitoring sudden infant death syndrome. The present invention fulfills this long-standing need and desire in the art.
The present invention is directed to devices and/or methods of monitoring sudden infant death syndrome (SIDS).
In one embodiment of the present invention, there is provided a system consisting of a sensitive optical rangefinder which senses the movement of a spot of light, projected onto the sleeping infant.
In another embodiment of the present invention, there is provided a method and/or system of using a laser, the radiant output of which is passed through a diffractive optic whereby a matrix of spots is projected into the crib. The movement of the infant is detectable by monitoring the movement of the image of the spots on a charge-coupled device (CCD). Alternatively, a light source such as a superluminescent infrared light-emitting diode (LED) can be used rather than a laser.
In another embodiment of the present invention, there is provided a system for monitoring movement of an infant, comprising: a light source which produces radiant energy; an optical device; and an imaging device.
In another embodiment of the present invention, there is provided a method of monitoring movement of an infant, comprising the steps of: producing radiant energy by a light source; coupling said radiant energy into an optical device so as to create a matrix of images; projecting said images into a field of interest; and detecting movement of said infant using an imaging device.
Other and further aspects, features, and advantages of the present invention will be apparent from the following description of the presently preferred embodiments of the invention given for the purpose of disclosure.